Cross-string cradle switch for a telephone set



Oct. 6, 1910 J. HOFER ETAL 3,532,845

RING CRADLE SWITCH FOR A TELEPHONE 8 Filed April 26, 1968 Patented Oct. 6, 1970 3,532,845 CROSS-STRING CRADLE SWITCH FOR A TELEPHONE SET Josef Hofer and Gunter Haage, Vienna, Austria, as-

signors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Apr. 26, 1968, Ser. No. 724,573 Claims priority, application Austria, Apr. 28, 1967,

Int. Cl. H0111 9/02 US. Cl. 200-166 Claims ABSTRACT OF THE DISCLOSURE Cradle switch contacts for a telephone handset are provided. The contacts are completed by cross-strings or springs supported by a base and/or by a cradle switch. Removal of a telephone handset (not shown) from the cradle causes certain springs to contact other springs and complete circuits to a telephone line.

This invention relates to a resilient contacting device for telephone sets, such as a so-called cradle switch.

The contacting device according to the invention is characterized in that a comblike actuating member having grooves in different depths is rotatably mounted about a point which is remote from these grooves..Resilient conducting wires, which are round or angular in crosssection, are provided. These wires are received by said grooves, extend at right angles to the longitudinal direction of the comblike actuating member and are held in position by grooves, noses, and clamping devices. A resilient conducting wire, which is round or angular in crosssection, is provided, which crosses the conducting wires close to the comblike actuating member and is also held in position by grooves, noses, and a clamping device and is limited in its freedom of movement by hooks. The resulting assembly is such that the actuation of the comblike actuating member opens normally closed contacts and closes normally open contacts and the crossing wire follows resiliently.

Furthermore, according to the invention, the clamping device provided in such contacting device and serving for directly holding the contact spring wires at least at one end consists of rectangular insulating walls. These walls are at right angles to the base plate and closed on three sides, serve to receive a square nut and are provided with through apertures for the contact spring wires. Through apertures for the connecting bolt and apertures for lugs of a cover plate are provided, and the ends of the contact spring wires are bent, preferably curved, and clamped between the cover plate and the nut held in the base plate by the lugs.

Further, according to the invention, the assembling operation is facilitated in that the clamping devices are arranged one beside the other in rows and in steps on different levels. In a development of this embodiment of the invention, the cover plate has a short lug for insertion into a corresponding aperture and an extended lug for insertion into another aperture and for passing out through a window of the step. A plug joint is adapted to be connected to said extended lug.

Further, according to the invention, the hooks are set back toward the clamping device and limit the movement of the crossing conducting wire before its end position so that it has a wider range of resilient movement at its free end and the conducting wires in contact with each other are self-cleaning because they are shifted relative to each other when urged against each other.

An embodiment of the invention will now be explained more fully with reference to the drawing.

The base plate 47 of a telephone set consists of insulating material and is mounted in a vertical position on a wall or rests on a table. A comblike actuating element is rotatably secured to said base plate. The handset of the telephone set, which is not shown, rests on the part 2 so that the comblike actuating member is rotated about the point 3 in a counterclockwise sense.

In this condition, the resilient wires 12 and 13 contact the U-shaped member 54, which extends substantially at right angles to the wires 12 and 13 and which is resiliently depressed to clear the stop faces of the hooks 25 and 26.

The wire contact springs 10 and 11 as well as 14 and 15 are thus lifted from the crossing wire contact spring 54. The wire contact springs are cambered.

According to the invention, the wire contact springs 10-15 are guided by grooves 1824 and noses 29-34 and by being fixed at their ends 46, 42 and at 43, 48 and 49. The wire contact spring 54 crosses the other wire contact springs substantially at right angles and its resilient movement is limited in an upward direction in that the spring 54 engages the nose of the hooks 25- and 26 and in a downward direction by the base plate 47. The wire contact spring 54 is guided according to the invention by the grooves 16 and 17 and by hooks 27 and 28.

The drawing shows only an example. A plurality of noses and grooves may be used for each wire contact spring.

The ends of the wire contact springs are preferably secured to a chamber 42, 43 ,or 48, 49, which is at right angles to the base plate. The nut 36 is first inserted into said chamber, then the end of the wire contact spring is placed on the nut. Finally a cover plate 37 is applied, which is formed with a through hole 38 for the bolt 35 and with lugs 39 and 40. The latter are passed through the holes 41 and are then reversely bent on the underside of the base plate so that the nut is held in position.

The bolt 35 holds all parts together. The bolt 35 and with it the connection of the parts is loosened for the connection of the external wires but the connection is re-established when the bolt is being re-tightened.

A different form of the cover plate 50 having a hole 51 is shown over the bolt. The lugs 52 and 53 are different too. The lug 53 is again passed through the hole 41 and reversely bent on the underside of the base plate 47 and passed out in a window of the vertical Wall of another step. A plug connection can then be attached to the end of the lug 53. This is particularly desirable with telephone sets because they can be serviced more quickly.

When the handset is lifted, the comblike actuating member 1 of insulating material rotates in the clockwise sense about the pivotal axis 3 so that the Wire spring 54 springs upwardly until it engages the noses of the hooks 25 and 26 in its end position. Under their own spring force, the Wire springs 12 and 13 move upwardly to clear the resilient wire 54. Depending on the depth of the slots 4 to 9 in the comb, the springs 10, 11 and 14, 15 approach the spring 54 when the same is held in position by the noses of the hooks 25 and 26. Finally, the springs 10, 11 and 14, 15. contact the springs 54.

This is the usual function of a cradle switch of a telephone set. Additional wire springs could obviously be provided, or single wire springs, in order to increase the number of contacts which can be controlled by the cradle switch. It is also possible to provide a plurality of crossing wire springs 54, e.g., in different planes.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

We claim:

1. A resilient contacting device incorporated in a telephone set and actuated by a telephone handset, comprising a base plate, a comblike actuating member having grooves in difierent depths rotatably mounted about a point aflixed to the base plate which is remote from said groves, wire contact springs, said wire contact springs received by the grooves and extending at right angles to the longitudinal direction of the comblike actuating member and held in position by additional grooves, noses and clamping devices on the base plate, a resilient wire spring, said resilient wire spring crossing the wire contact springs close to the comblike actuating member while being held by grooves and noses on the base plate, said resilient wire spring being limited in its freedom of movement by hooks afiixed to the base plate so that the actuation of the comblike actuating member opens normally closed contacts between the resilient wire spring and the wire contact springs and closes normally open contacts.

2. A contacting device according to claim 1, in which the clamping devices for directly holding at least one end of the wire contact springs consists of rectangular insulating walls at right angles to the base plate and closed on three sides, said walls receiving a square nut and provided with through apertures for the wire contact springs, through apertures for a connecting bolt, and apertures for lugs of a cover plate, and the ends of the wire contact springs are bent, preferably curved, and clamped between the cover plate and the nut and held in the base plate by the lugs.

3. A contacting device according to claim 1, in which the assembling operation is facilitated in that the clamping devices are arranged in rows one beside the other and in steps on difierent levels.

4. A contacting device according to claim 3, in which a cover plate has a short lug for insertion into a corresponding aperture and an extended lug for insertion into another aperture and for passing out through a window of the step, a plug joint adapted to be connected to said extended lug.

5. A contacting device according to claim 1, in which the hooks are affixed to the base plate and are set back toward the clamping devices to limit the movement of the resilient wire spring at its end position so that it has a wider range of resilient movement at its free end and the wire contact springs and the resilient wire spring in contact with each other are self-cleaning because they are shifted relative to each other when urged against each other.

References Cited UNITED STATES PATENTS 2,587,458 2/1952 Fritts. 2,747,144 5/ 1956 Beers. 3,060,784 10/1962 Holt. 3,330,916 7/1967 Bauer. 3,448,225 6/1969 Stromer 179-l59 HERMAN O. JONES, Primary Examiner US. Cl. X.R. l79159 

